Static frequency changer



May 8, 1928.

1,669,142 M. OSNOS STAT I C FREQUENCY CHANGER Filed Oct. 20. 1925 2 Sheets-Sheet l ENT RNEY

May 8, 1928. 1,669,142

M. OSNOS STATIC FREQUENCY CHANGER Filed Oct. 20. 1925 2 Sheets-Sheet 2 INVENT MENDEL O5 0 ATTORNEY Patented May 8, 1928.

UNITED STATES PATENT OFFICE.

MENDEL OSNOS, OF I BERLIN, GERMANY, ASSIGNOR TO GESELLSCHAIFT FOR DRAi ETLOSE TELEGRAPHIE M. B. 1-1., OF BERLIN, GERMANY, A CORPORATION OF GERMANY- S'I'ATIC FREQUENCY CHANGER.

Application filed October 20, 1925, Serial N0.'68,615, and in Germany September 16, 1924.

M invention relates to arrangen'icnts for changing electrical energy of one frequency into electrical energy of another frequency, and, more particularly, to such an arrangement in which there are no moving parts. The invention relates not only to frequency changing but also to modulation and more particularly to a. combined apparatus therefor.

The invention, in general, utilizes a Vheatstones bridge u-iagnetic circuit with a suitable primary circuit of the input frequency and a secondary circuit of the output or useful frequency associated therewith. One arrangement according to the invention is somewhat similar to that in German patent application No. 29,298 filed in Germany September .12, 1924, the corresponding United States application being filed under Serial Yo. 63.618 on October 20, 1925, wherein a scheme for modulation was disclosed, making use of a novel conductor formed of a core of conducting material provided with an outer layer or coating of magnetic material.

The usual type of frequency changer introduces high losses, and furthermore, it is extremely difiicultto dissipate the heat caused by its losses. This problem becomes especially acute at the high frequencies em ployed in short wave work. It is an object of my invention to overcome the difliculty of heat dissipation and to reduce'the losses accompanying the change of frequency.

It is a further object of my invention to combine controlling or modulating means with a frequency changing means in a simple manner requiring practically no additional apparatus.

Another object of the invention is to provide a frequency changer which will be cheap to manufacture and yet simple. and

..cfiicient in operation. Another object of this invention is to provide a frequency changer which will be adjustable and thereby eliminate the necessity of separate adjusting inductances.

Other objects Will be apparent from the following description and appended claims when considered with the accompanying drawings in which,

Fig. 1 is a diagrammatic arrangement of the conductors as in the former application,

Fig. 2 represents an arrangement of an old type frequency changer,

Fig. 3 represents an arrangement according to the invention,

liigs. 4: 5, 7, and 8 represent modifications, anc

Fig. 6 is a cross section, greatly exaggerated, of the novel conductor used according to the invention.

Figure 9 is a modification showing the application of telephony modulation to the high frequency energy.

In the former application a controlling arrangement for the high, frequency conductor has been described. Referring to Fig. 1, this arrangement in a fundamental form consists of a complex conductor made up of a pluralitv of conductors forming branches (1,, a a and a, arranged as shown. The branches are connected in a form somewhat similar to a Wheatstones bridge, the branches at, and a, being close to and parallel to branches at, and a, respectively. Each conductor or branch is formed of a core of conducting material 10 such as copper (Fig. 6) covered bya layer of magnetic material 11 such asiron or some alloy thereof. The layer of magnetic material is preferably very thin to give the necessary magnetization and heat radiating surface per unit of volume. The conductor for the current is traversed not only by the high frequency currents, but also by the con- 1 trolling or modulating currents. Relative to the high frequency current fed in at the axis K, K the arrangement is bifilar, that is, the high frequency current traverses the bifilar branches a, and a, in opposite directions and likewise the bifilar branches a, and (1,. For this current, the magnetic flux (stray flux) which does not pass through the iron sheath or covering, and jointly therewith also the stray inductance, are almost entirely elimi-- natcd. However, for the current in the 1 1 axis, the arrangement as here illustrated is notbifilar, and the stray inductance is undiminished. If the same is to be eliminated, the branches a, and a, must be turned about axis K K by an angle of about 180 degrees as shown dotted in Figure 1, a, becoming a,, Z), becoming 6,, and 1 becoming 1,

If one further examines the axis 1,, 1 in which the controlling or modulating current of useful energyof a whole multiple frequency, for at the axis 1 1 of the modulating currents, the secondary currents of a whole multiple value may be taken off, 1f

, at the other axis K K primary currents of basic high frequency are fed in.

Since it isfurthermore possible to eliminate at will, or, if desired, to increase both the primer as well as the secondary leakage (stray) in uctance independently of one-another by suitable formation of the complex conductor, as b elongation or sufficient deflection or ben ing away of the branches in different axes, this constitutes an excellent tuning means for the system whereby separate tuning variometers may be renderedwholly or partly dispensable.

Considering, for instance, a high frequen- 0 installation of the well known type as epicted in Fig.2 comprising a high frequency source 9, parallel capacitance C a seriescapacitance 0,, a tuning variometer L and a frequency changer T of any of the types heretofore well known, it will be seen that, in order to preclude useful or output currents of multiple frequency f, of the secondary circuit II from the primary circuit I, the variometer L must be chosen sufiiciently large to choke out the frequency f,; hence, it constitutes a considerable source" of losses. The frequency changer T may be a static frequency changer comprising a core of magnetic material such as iron with a primary and secondary circuit connected thereto, said circuits being connected either to the same winding, such as shown in the drawing or to separate windings, as is well known in the art. c

Now, this varicmeter L can be dispensed witlrif, in lieu of the customary current transformer the arrangement of a current conductor disclosed in the application above referred to is used. A connection of this sort .is depicted diagrammatically in Fig. 3. No frequency changer in the former sense of the term is here used. Instead, part of the leads are constructed in the manner of the conductor disclosed in the former application. The primary fundamental or basic current is here supplied at the axis 1, l and it flow in the branches a, a, as well as in the brane es a, and a, in the same direction. Hence, in this axis, the primary stray inductance remains, unchanged, and if of sufiicient value, it may be made use of to take the place of the self inductance of the dispensed with if the self inducance of the variometer L of Fig. 2, which may then be entirely dispensed with, or which, if condenser C instead of' being continuously variable is only variable in steps, may be replaced by a small regulatin variometer L (Fi 3 which only serves for overlapping or ri ging the increments or stepwise changes in condenser 0 However, even in this case the small variometer could be conductor serving as the current transformer is made variable for the axis 1 1,. As a simple example, consider the bending of the axis 1,, 1,, about the axis 70,, as was previously suggested, and which is indicated by the dotted lines in Figure 3.

The current required, for instance, for the auxiliary magnetization (most suitably direct current magnetization) is fed, for instance, from a battery 6 by way of a protective inductance d to the axis k, k, and from this same axis there is derived or taken off the secondary high frequency current of whole multiple frequency. The conductor serving as the frequency changer may be bifilar with reference to the direct current and the secondary current, and therefore is free from secondary stray inductance.

If'it is desired to eliminate the inductance L, of Figure 2, and if the primary stray inductance in the axis 1 1 is not high enough, itmay be increased in several ways. For example, the conductor in question may be lengthened. But a better scheme would be to wind it into a sufliciently great number of round or angular turns or spirals in order to concentrate the stray flux just as an ordinary coil concentrates the total flux. This has been illustrated in Figure 8. If desired, the resultin bifilar coil may be made in two parts relatlvely positioned in a variable manner, as for example, in a variometer, whereby the stray inductance for the axis 1 1 is raised to the desired large amount ing affected thereby. The latter, as heretofore, remains very low, in view of the fact that the conductors 'when rolled up remain bifilar with relation to the axis 70, k For telephony, a direct current may be varied by a microphone instead of a key. This, as well as a diagram for a variom'eter connection for the frequency changer, has been indicated in Figure 9.

For the purpose of keying and telephony work, it is most suitable to vary the direct current furnishedfrom the battery 6; although of course, the work of telegraphing or telephoning could also be accomplished. in some other of the various well known manners. For telegraphy, as an illustration, the direct current may be varied by key 20 as shown in Figure 3.

The terminals la, in, are most conveniently disposed in a symmetrical manner with reference to the terminals 1 1 but this is not absolutely necessary.

In case it is desired to diminish the primary stray inductance and to increase the secondary stray inductance, or if any relationship at all is to be established between them, this is made possible in any given case by the convenient shaping or bending of the branches making up the frequency changer. By bending or shaping the branches of the frequency changer making up a Wheatstone bridge the area enclosed by the sides of the Wheatstone bridge is altered, thereby varyin the stray inductance effects and giving adjustability to the frequency changer. Positioning of two adjacent branches in a single plane has been indicated in Figure 4, where (1, is a possible altered position of (1,. Such adjustable positioning may be applied to the complete bridge of Figure 3, the adjustment in each case depending upon the particular conditions to be met.

Furthermore, it is not absolutely neces-' sary to build the frequency changer of four like branches. Figs. 4 and 5 illustrate a construction comprising but two iron coated branches a and a, of like nature. In both cases the primary current is supplied at the axis 1 and 1 while the secondary current is taken off at the axis is, and 10,. In the case of Fig. 4 the battery serves at the same timeas a voltage divider, and therefore carries also the primary currents. In the case of Fig. 5 the battery 6 is again safeguarded against the primary currents by choke coil (2, while the voltage divider used consists of a bridge made up of an inductance e. The lower branches of the bridge may be capacitive as indicated in Figure 7, wherein the voltage divider consists of the capacitance 1, 2-

In the presence of extra high frequencies, forraisin the power and the efficiency it is a very a vantageous plan to maintain the iron of the conductor constituting the frequency changer in a state of incandescence, especially inthe vicinity of the critical temperature point of the iron.

Having described my invention, I am entitled to all modifications thereof that come fairly within its spirit and scope as set forth in the following claims:

1. A frequency. changer arrangement in cluding a branch circuit consisting of a core of conducting material surrounded by a layer of magnetic material whereby much of the flux caused by current in the branch cuts said branch only, a primary circuit contain: ing a source of a supply frequency connected to said branch, a secondary circuit of desired frequency connected to said branch and a source of auxiliary magnetization connectedto said branch.

2. A frequency changer arrangement including, a plurality of branches in the form of a Wheatstones bridge, two of said branches being relati ely adjustable and each comprising a core of conducting material surrounded by a layer of magnetic material whereby much of the flux caused by current in the branch cuts said branch only, a primary circuit containing a source of a supply frequency connected across diagonally opposite corners of said bridge, a secondary circuit ,of the desired frequency connected across the other corners of said bridge, and a source of auxiliary magnetization connected across one pair of diagonally opposite corners.

3. A frequency changer arrangement including, a plurality of branches in the form of a VVheatstones bridge, two of said branches being relatively adjustable and of compound material, each comprising a core of conducting material surrounded by a layer of magnetic material whereby much of the flux caused by current in the branch cuts said branch only, a primary circuit containing a source of a supply frequency connected across diagonally opposite corners of said bridge, a secondary'circuit connected across the other corners of said bridge, and

.a"source of auxiliary magnetization connected across one pair of diagonally opposite corners, said branches of compound material being adapted to be heated to work the magnetic material at its critical temperature.

4. A frequency changer arrangement including, a plurality of branches in the form of a Wheatstones bridge, each branch comprising .a core of conducting material surrounded by a layer of magnetic material whereby much of the flux caused by current in the branch cuts said branch only, a primary circuit containing a source of a supply frequency connected across diagonally opposite corners of said bridge, a secondary work circuit for the desired frequency connected across the other corners of said bridge, and a source of auxiliary magnetization connected across one pair of diagonally opposite corners, said branches being adapted to'be adjusted relative to each other to control the stray inductances of said circuits.

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5. A frequency changer arrangement inon'ally opposite corners, said branches being adjustable to control their stray inductance. 6. A frequency changer arrangement including, a plurality of branches in the form 8 of a Wheatstones bridge, each branch comprising a core of conducting material surrounded by a layer of magnetic material in the branch cuts said branch only, a priply frequency ponnected across diagonally opposite corners of said bridge, a secondary circuit for the desired frequency connected across the other corners of said bridge, and

a source of auxiliary magnetization connected across said other corners, said branches being adapted to be adjusted relative to. each other to adjust the stray inductances of said circuits.

7. A frequency changer arrangement including, branches in the form of a Wheatstones bridge, each of a plurality of branches being made of compound material comprising a core of conducting material surrounded by a layer of magnetic material whereb much of the flux caused by current in the ranch cuts said branch only, a primary circuit containing a source of a supply frequency connected across diagonally opposite corners of said bridge, a'secondary circuit for the desired frequency connected across the other corners of said bridge, and a source of auxiliary ma netization connected across one pair of iagonally opposite corners, the compound branches being arranged in bifilar relation.

8. A frequency changer including a plurality of branches in the form of a Wheatstones bridge, saturable impedances in at 40 least some of said branches, a primary 'circuit containing a source of a supply frequency connected across diagonally opposite cuit for the desired frequency "connected 5 across the. other corners of said bridge, said branches being positioned in bifilar relation.

9'. A frequency changer including a plurality of branches in the form of aWheatstones bridge, saturable impedances in at least some of said branches, a primary circuit containing a. source of a supply frequency connected across diagonally opposite corners of said bridge, a secondary clrcuit forthe desired. frequencyconnected across g the other corners of said bridge, and a source of niagnetizingaenergy arranged for magnetization of the saturable impedances, said branches being positioned in bifilar relation with respect to the path of the secondary no energy. 1 I

10. A frequency changer including a plurality of branches in the form of a Wheatstones bridge, saturable impedances in at least some of said branches, a primary cirwhereby much of the flux caused by current 10 mary circuit containing a source of a supcorners of said bridge, and a secondary circuit containing a source of a supply frequency connected across diagonally opposite corners of said bridge, a secondary circuit energy.

11. In combination, a network of compound conductors connected like the branches of a Wheatstones bridge, and a source of current connected across the bridge, each compound conductor being composed of a core of conducting material surrounded by a layer of magnetic material whereby much of the flux caused by current in the conductor cuts said conductor only,-

the branches being so relatively positioned that the remaining or stray flux caused by current from said source is neutralized.

12. In combination, a network of compound conductors connected like the branches of a Wheatstones bridge, and a source of current connected across the bridge, each compound conductor bein composed of a core of conducting materia surrounded by a layer of magnetic material whereby much of the flux caused by current in the conductor cuts said conductor only, the branchesbeing so relatively positioned that the .remaining or. stray flux caused by current flowing .thruethe bridge from one corner to a diagonally opposite corner is neutralized.

13. A frequenc changer including a single bifilar woun inductance comprising a plurality of branches of a Wheatstones bridge, and circuits associated therewith, said inductance being wound of a compound conductor composed of a core of conducting material surrounded by a layer of magnetic material.

14. A frequency changer including a single bifilar wound inductance com rising four branches of a Wheatstones bri ge, and input, output, and saturating circuitsuzssociated therewith, said inductance being wound of a compound conductor composed of a core of conducting material surrounded by a layer of magnetic material.

15. A frequency changer comprising a Wheatstones bridge including two wound,

inductances adapted for variable relative positioning, each of which comprises two of the branches of the said Wheatstones bridge, and input, output, and saturating circuits associated therewith, said inductance bein wound of a compound conductor composed of a core of conducting material surrounded by a layer of magnetic material.

16. A frequency changer having as its harmonies generator a Wheatstones bridge the four branches of which are impedances, a plurality of which include a compound conductor comprising a core of conducting material surrounded by a layer of magnetic 5 material. I

17. A frequency chan er having as its harmonics generator a W eatstones bridge,

the four branches of which are impedances, a plurality of which include a compound conductor which is movable and which cum prises a core of conducting material sur-= rounded by a layer of magnetic material mum came 

